Indexed by:Journal Article

First Author:Li, Jianbo

Correspondence Author:Li, JB (reprint author), Chongqing Univ, Sch Mat Sci & Engn, Chongqing 400044, Peoples R China.; Liu, Y (reprint author), Cent S Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China.

Co-author:Lu, Xiaofang,Tang, Shan,Liu, Yong,Liu, Bin,Wang, Yan

Date of Publication:2018-04-01

Journal:METALS

Included Journals:SCIE

Document Type:J

Volume:8

Issue:4

ISSN:2075-4701

Key Words:TiAl alloy; Zener-Hollomon parameter; Nb particle; fracture toughness

Summary:Hot compressive deformation behaviors of a powder metallurgy Ti-45Al-5Nb-0.4W/2Nb (at. %) were investigated at strain rates from 0.001 s(-1) to 1 s(-1) and temperatures from 1050 degrees C to 1200 degrees C. The Zener-Hollomon (Z) parameter can affect the hot deformation mechanism significantly. At a high Z condition, Nb particles played an important role in coordinating the deformation. At a low Z condition, deformation of Nb particles accompanied by dynamic recrystallization (DRX) can act as a dominant softening mechanism. The as-forged pancake exhibits a short rod-like particle-toughened equiaxed matrix. For notched three-point bending (3PB) tests, the fracture toughness of an Nb-particles-toughened high-Nb-containing duplex phase-gamma-TiAl alloy was hardly affected by the loading rate, presenting a peak fracture toughness of about 12.9 MPa.m(1/2). The toughness of the present alloy can be improved by ductile Nb particles. A model based on the Griffith-Orowan-Irwin relation was constructed, which is quite accurate to predict the facture toughness of the present specimen using tensile properties.